Sewing machine



Sept. 10, 1946 SEWING MACHINE Fi led Feb.- 25, 1944 fy 2 A a INVENTOR.

J. NACHMAN 2,407,342

Patented Sept. 10, 1946 UNITED STATES PATENT OFFICE SEWING MACHINE Joseph Nachman, Philadelphia, Pa.

Application February 25, 1944, Serial No. 523,871

4 Claims.

This invention relates to the art of sewing or stitching machines. More particularly, it pertains to apparatus coordinated for functioning in connection with sewing or stitching machines to examine or inspect the results of a stitching operation. While the invention is of substantial application, a primary embodiment thereof pertains to apparatus for the production of open stitch work. exemplified by faggoting, which is adapted to ascertain any defects of stitching as they occur and to automatically control the operation of the machine under such circumstances, as by terminating the stitching operation.

It is well recognized that the operation of a sewing or stitching machine is not foolproof, and that difficulties may be frequently encountered which manifest themselves in the form of defective machine operation and by imperfection of the articles produced. In the case of openwork stitching or faggoting, this may be due to faulty functioning of the needle, thread breakage, failur of thread supply, improper thread or fabric feeding, et cetera.

It is known to provide a sewing machine with an attachment which may function to cut-off or stop the same where a metallic object, such as a metal fastener element, has not been properly sewn to an electrically non-conducting support, such as a fabric. Thus, the metallic fastenerelement may be embraced in an electric circuit which may become effective for terminating the operation of the machine only in the situation where the surface of the metallic fastener-element has not been properly insulated by thread sewn thereover in the course of attaching the same to a fabric or the like. Similarly devices have been contemplated for cutting-off a sewing machine from its normal course of operation where the thread supply to the needle has become defective due to breakage or for any other reason. However such devices are not adapted to function in the capacity of examining or inspecting the stitching characteristics as applied to the work produced.

In general, the prior art devices designed for controlling the operation of the sewing machine have not been adapted to inspect open-work stitching, such as faggoting, during the course of producing the same, and capable of directly and automatically terminating the machin operation in the event of work discrepancies or imperfections, without resort to any supplementary, superficially attached electrical conducting means. In fact, there appears to be no expedient device that has been available heretofore which is directed to the scrutinizing or inspecting of open-work type of stitching, as to its detailed perfection and adapted to control the functioning of the machine.

It is an object of the present invention to obviate such difficulties and uncertainties as hereinabove referred to, and particularly such as usually manifest themselves in the operation of a sewing machine while producing open-work stitching or faggoting.

Another object of the invention is to provide a simple, rugged means adapted to inspect the stitching operation of a machine and to automatically terminate said operation in the event of any imperfections manifested.

Still another object is to attain an effective device for scanning open-work stitching immediately upon its production by an appropriate machine, and automatically adapted to stop the functioning of said machine where improperly stitched work is produced.

An additional object of the invention is to present an expedient attachment for a stitching machine adapted to inspect or examine the perfection of a faggoting operation, and to automatically cut off the machine in the event that any imperfections develop.

It is a further object of the invention to devise an apparatus adapted for examining the results of an open-work stitching or faggoting operation immediately as it issues from the zone of stitching, while simultaneously guiding the article produced by the said faggoting operation.

Other objects, advantages, and features of the invention will become apparent from the following description to be read in connection with the accompanying drawing in which similar elements are designated by like numerals.

Figure 1 is a fragmentary side elevation of the stitching machine showing partly in section the inspecting or examining attachment in contact with the work of a faggoting operation.

Figure 2 is a cross-section taken on line 22 of Figure 1.

Figure 3 comprises a partial front elevation of the device viewed in the direction of issue of the finished article.

Figure 4 is a fragmentary detail, partly in section, indicating the inspecting finger riding on the faggoting stitches which serve to insulate said finger from contact with an electrical conducting plate for supporting the stitch work below the zone wherein said inspecting finger operates.

Figur 5 is a view similar to that shown in Figure 4, but with the inspecting finger in contact with said electrical conducting supporting plate through broken stitches of the open-work stitching, such as faggoting, thereby illustrating the position of the finger in the event of an imperfection in the article produced.

Figure 6 is a diagrammatic showing of an electric circuit for Operating the stitching machine, as well as automatically terminating its action in the event of contact between the inspecting finger and the electrically conductive supporting plate.

Referring more particularly to the preferred embodiment of the invention as presented by the various figures of the drawing, numeral 1 broadly indicates a sewing or sitching machine head to which a needle bar 2 is attached. Needle 3 is is aflixed to said needle bar 2 by means of a screw element 4 in accordance with conventional practice, and is coordinated with foot 5 for performingthe stitching operation. Mounted on foot 5 is a bracket 5, by a screw means 1, and integral with the said bracket is a bifurcated arm 53. A point of rotation or pivot 9 may project through appropriate openings in the aforesaid bifurcated arm of the bracket, and mounted for rotation thereon is the inspection or examining finger IE1 adapted for contact with the article 253 issuing from the Zone of the needle operation. Desirably, the contact of finger It with openwork stitching of 23 is facilitated by the action of a spring means I2, which may be seated on pivot 9 as shown in Figures 1-3. A dotted showing II is presented of the spring depressed finger Ill raised out of contact with article 23 against the tension of spring means l2, where circumstances dictate.

The work tape forming the edges [3 of the faggoting is supported on a frame or table I! which is of non-conducting material in accordance with the usual design of stitching machines. Beneath the zone of contact of examining finger ID, the article 23, subject to mechanical inspection, is supported by an electrical conducting plate l4, desirably metal. Elements l5, l6 designate electric wires comprising elements of the circuit shown in Figure 6. An electro-magnet or solenoid I8 is adapted to control magnetic switch l9 under predetermined conditions. The

motor for operating th sewing machine is designated as 2! while the source of direct current for the operation of the solenoid is indicated as 2|. A manually operated switch 22 is also embraced in the showing of Figure 6.

In the operation of the apparatus, the parallel tape edges l3 are directed beneath the zon of operation of switching needle 3 where the openwork stitching or faggoting is supplied to connect the edges. From there, the finished article 23 is passed beneath the area of contact of the examining finger l0. Desirably as the completed article, such as faggoted tape 23, proceeds from contact with IE, it may be fed to a reel or similar means not shown which is adapted to maintain the tape under a reasonable degree of tension and in uniformly extended condition as the openwork stitching operation proceeds.

Where the onen-work stitching or faggoting is devoid of imperfections, examining finger Ill will ride thereover, desirably fitting into the shallow groove or depression determined by the edges I3, will appear from Figure 3. It will thereby function as a guide means for the tape as it progresses through the stitching operation to be wound upon a distributing reel, while also serving as a mechanical inspecting or examining device. As long as there is no break or imperfection in th stitching uniformity, inspecting finger ill will be prevented from contacting base plate [4 by the intervening stitches, as indicated in Figures 1 and 4.

In the event that a break or imperfection is manifested by the open-work stitching, resulting in a space or gap between stitches large enough to permit the inspecting or examining finger IE! to pass through and contact conducting plate 14, the circuit of solenoid l8 shown in Figur 6 will be closed, provided manually operated switch .22 has been previously closed. As the solenoid it becomes energized upon the closing of the circuit within which it is embraced, it will attract magnetic switch 19, resulting in opening the circuit in which the sewing machine motor is located. Accordingly, any undue gap in the stitching or faggoting operation will cause an automatic break in the circuit determining the operation of the sewing machine, thereby aliording opportunity for correction of the dilhculty involved and permitting resumption. of the operation under desired conditions.

As above indicated. by devising the examining finger it of a dimension to embrace the stitching between edges E3 of the tape, the said finger will function as a guide means as well as an examining device adapted to control the operation of the stitching machine motor. This is of material significance in that it enables simplification of the attachment by making possible the omission of collateral guide means, and in addition permits of a distinctly more efficient operation than heretofore.

As shown in the figures of the drawing, the dimension of the contact surface of the examining finger may desirably embrace two consecutive stitches 22 i. Expediently, the dimension may be such as to include two stitches along a median line drawn longitudinally of the article, i. e., parallel to the tape edges. However, it is not intended to be restricted to any particular dimension or design of inspecting finger, either taken as a whole or with respect to its contact surface. It is merely requisite that the design and dimension are such as to prevent the finger means passing through the interstices determined by the respective threads or stitches into contact with base plate It or its equivalent, except where a predetermined degree of imperfection or lack of uniformity, et cetera, is encountered. Thus examining finger It may be designed to embrace three or four stitches, and in some instances, merely one may suflice. Similarly, its characteristics may be such as to detect a breakage or imperfection only where two consecutive stitches or an equivalent thread supply are involved. In brief, it is merely essential that the finger be adapted to maintain contact with the stitches where no imperfection or lack of uniformity of a predetermined nature is apparent, and to make contact with conductlilg plate l immediately upon the passage ther beneath of a predetermined extent of imperfection or lack of uniformity.

While the invention has been described in con nection with open-stitch work as illustrated by faggoting, in which field of application it is particularl effective, it is not intended to be restricted to this adaptation. Thus, it may be applicable in the art of weaving or to other fields where the characteristics of the material contemplate distinct interstices or gaps between the thread or fibre determining its texture.

It will be apparent that a simple, effective apparatus is provided for expediently scrutinizing the characteristics of the work produced by a stitching machine, parti ularly in connection with the art of open-wori stitching or the like. t enables a control of machine operation, dependent upon the perfection or uniformity of the article produced, not heretofore known in the open stitch work art.

While I have described my invention in accordance with desirable embodiments, it is obvious that many changes and modifications may be made in the details of construction and in the combination and arrangement of parts, without departing from the spirit of the invention as defined in the following claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a stitching machine, the combination of a table, a presser foot and a needle operatively associated therewith, a source of power for the machine and means for cutting ofi said source of power to stop the machine including a circuit having therein a solenoid, a contact plate and a work engaging finger, said plate being positioned for contact with the stitched material at one side thereof as it issues from the needle and presser foot, the finger being operatively supported at the other side of the material and so disposed as to make contact with and complete the circuit through the plate, the construction and operation further being such that the said finger contacts said plate only upon passage of an imperiection in the stitched material.

2. In a stitching machine, the combination of a table, a presser foot and a needle operatively associated therewith, a source of power for the machine and means for cutting off said source of power to stop the machine including a circuit having therein a solenoid, a contact plate and a work engaging finger, said plate being positioned for supporting the stitched material as it issues from the needle and presser foot, the finger being operatively supported above the material and positioned for making an electrical contact with the plate, the construction and operation being such that upon passag of properly stitched material, the finger is insulated from the plate, but upon passage of material in which stitching is defective, the finger shall move into engagement with the plate thereby to close the circuit.

3. In a stitching machine, the combination of a table, a presser foot and a needle operatively associated therewith, a source of power for the machine and means for cutting ofi said source of power to stop the machine including a circuit having therein a solenoid, a, contact plate and a work engaging finger, said plate being positioned for supporting the stitched material as it issues from the needle and presser foot, the finger being operatively supported above the material and positioned for making an electrical contact with the plate, the construction and operation being such that upon passage of properly stitched material, the finger is insulated from the plate, but upon passage of material in which stitching is defective, the finger shall move into engagement with the plate thereby to close the circuit, said finger also being so formed at its fabric engaging end as to guide the stitched portion of the material.

A. In a stitching machine, the combination of a table, a presser foot, and a needle operatively associated therewith, a source of power for the machine and means for cutting off said source of power to stop the machine including a circuit having therein electrically responsive means, a contact plate and a work engaging finger, said plate being positioned for contact with the stitched material at one side thereof as it issues from the needle and presser foot, the finger being operatively supported at the other side of the material and so disposed as to make contact with and complete the circuit through the plate, the construction and operation further being such that the said finger contacts said plate only upon passage of an imperfection in the stitched material.

JOSEPH NACHMAN. 

